| Popis: |
In December 2007, a French decree related to hydraulic structures (levees and dams) has introduced for owners the necessity to produce a hazard study for each levee system. On the river Loire, three major class A* state levee systems are present and protect three main urban areas, Orleans, Tours and Authion representing some 240 000 inhabitants. Around 40 class B* and C* levee systems are also present on the river Loire and its tributaries representing 600 km of levees and requiring such hazard studies. In order to have a homogenous method to do these specific risk assessment studies on river Loire levees, a new model named CARDigues (for Levee Breach Hazard Calculation) was developed in a partnership with DREAL Centre-Val de Loire, Cerema and Irstea. This model enables to approach the probability of failure on every levee sections and to integrate and cross different “stability” parameters (topography, embedded structures, geology), hydraulic solicitations and observations from visual inspections or instrumentation results considered as disorders (seepage, burrowing animals, vegetation, pipes, etc.). This model and integrated tool CARDigues enables to check for each levee section, the probability of appearance and rupture of five breaching scenarios initiated by: overflowing, internal erosion, slope instability, external erosion and uplift. It has been recently updated and has been applied on several levee systems by different contractors. The article presents the CARDigues model (V28.00) with examples on river Loire and how it is currently used for a relevant and global levee system diagnosis and assessment. Levee reinforcement or improvement management is also a perspective of applications for this model CARDigues. (* levee classes are function of levee height and protected population) |
